Rotary cement-burning kiln



Jan. 8, 1924,

. 1,480,319 M. VOGELLJGRGENSEN ET AL ROTARY CEMENT BURNING KILN Filed Jan. ,1

Jan. 8 1924. I 1,480,319 M. VOGEL-JGRGENSEN ET AL ROTARY CEMENT BURNING KILN Filed Jan. 6, 1923 2 Sheets-Sheet 2 Patented Jan. 8, 1924.

UNITED STATES 1,4sq,319 PATENT oFncE.

. MIKAEL VOG-Im-J'ORGENSEN AND KRISTIAN MI DDELBOE, OF FREDERIKSBIBG, NEAR COPENHAGEN, DENMARK, ASSIGNORS TO I. L. SMIDTH & 00., OF NEW YORK, N. Y.,

A CORPORATION OF NEW JERSEY.

ROTARY CEMENT-BURNING KILN.

Application filed January 6, 1923. Serial No. 611,201.

To all whom it may concern:

Be it known that we, MIKAEL VOGEL-JR- GENSEN and KRISTIAN MIDDELBOE, sub ects of the King of Denmark, residing at Frederiksberg, near Copenhagen, Denmark, have invented certain newv and useful Improve ments in Rotary Cement-Burning Kilns, of which the following is a specification.

By the use of rotary cement burning k lns adapted to burn raw materials containing water there will, as a thermal calculation of the kiln will show when the gases have left the burning zone, the carbon-dioxide, expelling zone, and the heating zone'of the kiln, always be more heat available in the gases than the heat required to evaporate the moisture contained in the raw materials. Even in case the raw materials, after wet preliminary treatment, are supplied to the kiln in shape of slurry, the gases will leave the kiln with a considerable surplus of heat.

Various methods of utilizing this surplus of heat in the gases have been proposed, for instance to dry a surplus of raw material in the ln'ln, and to remove this surplus material in order t6 burn it in a separate kiln, to divert a. quantity of combustion gases corresponding to the surplus quantity of heat by way of suitably located 0 ening in the wall of the kiln, or to cut the iln in two between its burning zone and its smoke discharge end, and to insert at this point a flue passing a boiler plant or the like which may utilize the surplus heat.

A drawback common to these methods is that they involve a complication of the plant. The first mentioned method causes the plant to be quite costly, inasmuch as two kilns are 40v required, and the second and third methods involve the drawback that tightenings must be used at the passage from the rotary kiln proper to the stationary parts adapted to catch the gases and direct them from the kiln into the flue for the diverted gases, or from the burning zone of the kiln into the drying zone of the same, respectively. Such tightenings involve great technical dlfliculties.

The present invention supplies a solution of the problem by which the above mentioned surplus heat becomes easlly accesslble for various uses in a manner givlng a quite simple and cheap plant and, furthermore,

obviating the tightening difliculties and 210- 66 companying loses due to entrance of false air, which are, as mentioned above, the principal drawbacks of the known methods.

According to the present invention the problem is solved by keeping a certain quantity of the smoke, otherwise in contact with the moist raw-material in the kiln, apart from the said material and the remaining quantity of the smoke on a certain length of the kiln situated between its burning-zone and its feedin -end (outlet of combustiongases). There y it will be obtained that the portion ofthe smoke, kept apart from the raw material and the remainin portion of the smoke will remain dry an leave the kiln at a higher temperature than in the case of previous kiln-constructions, while obviously the remaining portion of the smoke which continues its passage in contact with the moist material, will be cooled gradually down and absorb more moisture per unit of volume than it would, in case no portion of the smoke had been diverted from contact with the moist raw material.

In order to carry this principle into eifect, according to which a. certain quantity of smoke is separated from the remainder, there may be inserted, in the portion of the k 1ln above mentioned, one or more tubes enclrcled by the kiln, for instance a centrally disposed tube by way of which the separated portion of the combustion gases the temperature of which is desired to-be maintained high, is diverted, while'the raw material and the remaining portion of the combustioh gases are allowed to pass outside of this or L these special flues, perhaps through special closed tubes disposed inside, of the shell of the kiln. 1

a By extending the said fiue or flues for the diverted gases beyond the supply-end of the kiln, and by continuing it or them to the place where the gases are to be utitlized, an division of the. kiln or openings in the she I of the latter for discharge of smoke, and corresponding stationary parts with tight 'enings against the kiln will be entirely.

avoided.

By inserting, at a suitable point in the separate flue, a suction device it becomes practicable to divert from the kiln exactly the quantity of gases (heat) needed for desired purpose, so that only exactly the neoillustrated in outline emry quantity of gases (heat) remains at disposal for drying the raw material. The smoke temperature in the chimney may therefore be reduced down to the limit determined by condensation of steam or sulphurous acid. in the chimney, and the kiln may therefore be madeto work in fully rational manner and economically at all outputs.

The separated gases may be improved by admixture, within or outside the kiln proper, of solid or fluid fuel which will further increase the temperature of the gases bly givin ofi' gas to be subsequently burnt. he com. ustion of the gas thus developed may be effected at any desired place by sup-- plg ing air to the smoke at the said place. be here described longitudinal division of the kiln is not to be confounded with the so-called cross-insertions, i. e., division of the cross-section by means of longitudinal partitions in such a manner that all of these compartments of the cross-section are assed by the flow of material as well as y the.

gases,'the object of this arrangement is quite another one, namely to increase the surface ofi'ered by the kiln wall to the raw material in order to attain, thereby, a more eflicient desiccation of the latter (evaporation of moisture).

One construction of a kiln plant arranged in accordance with the present process is on the drawing, where- Fig. 1 shows a longitudinal section of the smoke discharge end of the kiln and a boiler plant belonging thereto, and

Figs. 2 and 3, respectively, show a crosssection of the kiln alon the line II--II in Fig. 1, and a longitu nal section of the same along the line III-III in bi 2.

In the smoke-discharge end of file kiln, the space inside of the kiln shell 1, in this construction is subdivided, by inserted iron partitions lined with fireproof material, into ve tubes, one of which, the interior centrally disposed tube 2, projects out from the end of the kiln through the usual dust chamber 3, and opens. into another dustchamber 4. The other four tubes 5 are grouped outside of this tube, a space 6 closed at both ends of the system of tubes b means of walls 7 being left free between a the tubes.

Through the centrally disposed tube 2,

the portion of the smoke to be utilized is dischar ed and, in the construction of the plant s own, directed through the .dust chamber 4 to a boiler 8 and thence, through I an economizer 9 and a suction pan 10, to a special compartment 11 in the chimney. The

, suction pan serves, as mentioned above, to

regulate the quantity of smoke directed through the tube 2 and the boiler plant.

The outer tubes 5 afiord passage artly for the remaining portion of the smo e, which escapes by way of the dust chamber 3, to a compartment 12 ofthe chimney, and part- 1y--in opposite direction-to the slurry, which is introduced into the kiln by way of a duct 13.

. In the shell of the kiln openings 14 are arranged for the outer air, which will circulate through these holes to the space 6 between the tubes 2 and 5 and, thereby, prevent the" tubes 17 from becoming overheated and burnt. The kiln is supported, as usual, on a rin 15 with rollers 16.

In or er that the central tube 2, the temperature of which is far higher than the temperature of the outer tubes 5 may expand so freely, onlyits inner end (to the left) 1s firmly connected to the outer tubes and thereby to the kiln shell while its outer an (to the right) may freely -slide between the the outer tubes.

Instead of the separated smoke bein directed through the central tube 2, an the remaining smoke and the slurry through the outer tubes 5, the tubes maybe used in op: posits manner the slurry duct 13 being then directed into the tube 2, and the boiler plant 8 being connected to the duct chamber 3 in stead of to the chamber 4.

lt'will be seen, furthermore, that one or more of the tubes, for instancethe tube 2, may very well be stationary and extend from the outside into the kiln, instead of vice versa, and thus not partake of therotation of the kiln.

Finally it may be noted that in the c0n-v100 struction shown only two additional tighteningsbeing easy to construct and not causing any mconveniences are introduced, namely the tightening between the smoke tube 2 and an outer end wall 7 (to the right), and the tightening between the smoke tube 2 and the partitlon between the chambers 3 and 4.

Having now particularly described and ascertained the nature of our said invention 1111 e and. in what manner the same is to be performed, we declare that what we claim is 1. In a rotary ln'ln, a plurality of tubes open at bothiends extendin len hwise of the kiln and of less length than t e kiln arranged about a central tube adapted to serve as a flue for products of combustion from the burning zone of the kiln, means for drawing said products I of combustion through said flue, the tubes surrounding the the kiln and of less length than the kiln, arranged about a central tube adapted to serve as a flue for products of combustion from the burning zone of the kiln, and extending through said chamber, 'means for drawing said products of combustion through said flue, the tubes surrounding the central flue having their upper ends in com: munication inside a chamber provided with an outlet in communication with said first chamber, an' outlet for volatile products treated to .the upper ends of said surround- I tubes.

in ln testimony whereof we aflix our signatures, December 11, 1922.

MIKAEL VOGEL-JORGENSEN. KRISTIAN MIDDELBOE.

Witness: A

GILBERT AsK. 

